Magnetic latch assembly



5, 1959 P. ROBINSON 2,901,278

MAGNETIC LATCH ASSEMBLY Filed June 17, 1957 Fig. l

26 Fig. 3

INVENTOR. PRESTON ROBINSON AGENT) United States Patent MAGNETIC LATCH ASSEMBLY Preston Robinson, Williamstown, Mass., assignor to North American Philips Company, Inc., New York, N.Y., a corporation of Delaware This invention relates to a magnetic latch assembly and more particularly to a magnetic latch device for doors and other similar applications.

An object of the present invention is to provide a relatively simple magnetic latch assembly which provides a greater distance of useful attractive force than heretofore known.

Another object of the present invention is to provide a latch construction which can be closed and opened with a minimum of effort and which, when closed, securely maintains the door in a latched condition.

The above and other features, objects and advantages of the present invention will be fully understood from the following description considered in connection with the accompanying illustrative drawings.

Fig. 1 is a partial section and a partial side elevation view of the magnetic latch device embodying my invention in an open position and,

Fig. 2 is a partial section and a partial side elevation view thereof in a closed position,

Fig. 3 is a section view of the latch device as applied to a door.

Referring more particularly to the drawings, the magnetic latch device embodying my invention comprises a pole piece 2 which may be attached to a door jamb 4. A magnet 6 is mounted on the pole piece 2. The magnet 6 is provided with a preferably cylindrical aperture 8 which extends completely through the magnet.

An elongated holder 10 is pivoted at one end thereof at 12. Such holder 10 is provided with a portion 11 constituting :a pole piece. At the other end of the holder 10, there is provided an aperture 14 in which a preferably cylindrical pole piece 16 is positioned with a sliding fit. In this regard, the air gap between the pole piece 16 and the pole piece 11 is relatively small. In the posi tion of the device shown in Fig. 1 a leaf spring 18 holds pole piece 16 in its projected or forward position. Rivets 20 fix one end of spring 18 to the holder 10. Pole piece 16 is provided with a shoulder portion 22 and an end portion 24 shaped correspondingly to the aperture 8 of magnet 6. The pole piece 16 may be made of a good magnetic material such as soft iron, while the pole pieces 2 and 11 may be made out of cold rolled steel.

Fig. 3 discloses the latch device in accordance with the present invention as applied to a door. In this instance, the door jamb 4 has the magnet 6 and pole piece 2 mounted therein which function as a strike plate. Pole piece 16 acts as the bolt of the device and is mounted in door 26 having a handle 28.

The operation of my device is as follows: The loose pole piece 16 is held in its forward or projected position by spring 18 when the magnetic latch device is open as seen in Fig. 1. However, as the pole piece 16 is moved toward pole piece 2 the gap G is narrowed. Pole piece 16 then commences to enter the corresponding shaped aperture 8 in magnet 6. The gap G therefore narrows and pole piece 16 becomes attracted by magnet 6 and, is drawn to a seating position on the pole piece 2 secured 2,901,278 Patented Aug. 25, 1959 ice to, for example, a door jamb. The holder 10, therefore, in that instant of time occupies the position shown in broken lines in Fig. 2 and the shoulder 22 immediately thereafter forces the spring 18 in an upwards direction. Thus, since the gap G1 is within the influence of the magnet 6, pole piece 11 is attracted to the magnet against the resistance of spring 18 until pole piece 11 is seated on magnet 6 as shownin full lines in Fig. 2. It should be noted that in the present construction a useful attractive force over the distance (d) is achievedwThe distance is much greater than would be the case if the aforesaid parts were rigidly assembled in accordance with known practice.

While I have shown and described the preferred embodiment of my invention, it will be understood that the latter may be embodied otherwise than as herein specifically illustrated or described and that in the illustrated embodiment certain changes in the details of construction and in the arrangement of parts may be made without departing from the underlying idea or principle oi the invention within the scope of the appended claims.

What is claimed is:

1. A magnetic latch assembly comprising a support, a first pole piece, means securing said first pole piece to said support, an apertured magnet mounted on said first pole piece with at least a portion of said first pole piece forming a seat closing one end of said aperture, a holder mounted for independent limited movement to and from said apertured magnet, a part of said holder being a second pole piece with an aperture therein, a third pole piece having a face portion shaped complementary to said magnet aperture, said third pole piece having a sliding fit in the aperture of said second pole piece whereby when said holder is moved toward said magnet said third pole piece is drawn by magnetic force into said magnet aperture and seated on the seat of said first pole piece and said second pole piece is drawn into engagement with said magnet.

2. A magnetic latch assembly comprising a support, a first pole piece, means securing said first pole piece to said support, an apertured magnet mounted on said first pole piece with at least a portion of said first pole piece forming a seat closing one end of said aperture, a holder mounted for independent limited movement to and from said apertured magnet, a part of said holder being a second pole piece with an aperture therein, a third pole piece having a face portion shaped complementary to said mag net aperture, said third pole piece having a sliding fit in the aperture of said second pole piece, a spring normally biasing said third pole piece toward said first pole piece whereby when said holder is moved toward said magnet said third pole piece is drawn by magnetic force into said magnet aperture and seated on the seat of said first pole piece and said second pole piece is drawn into engagement with said magnet.

3. A magnetic latch assembly comprising a support, a first pole piece, means securing said first pole piece to said support, an apertured magnet mounted on said first pole piece with at least a portion of said first pole piece forming a seat closing one end of said aperture, a holder mounted for independent limited movement to and from said apertured magnet, a part of said holder being a second pole piece with an aperture therein, a third pole piece having a face portion shaped complementary to said magnet aperture, means including a leaf spring for maintaining said third pole piece with a sliding fit in the aperture of said holder whereby when said holder is moved toward said magnet said third pole piece is drawn by magnetic force into said magnet aperture and seated on the seat of said first pole piece and. said second pole piece is drawn into engagement with said magnet.

4. A magnetic latch assembly comprising a door jamb,

3 a first pole piece, means securing said first pole piece to said door jamb, an apertured magnet mounted on said first pole piece with at leastfa portion of said first pole piece forming a seat closing one end of said aperture,

magnet While the same slides over the third pole piece.

5. A magnetic latch assembly as claimed in claim 4 wherein one of said pole pieces is constituted of soft iron and the other of said pole pieces are constituted of cold a-hol'der on a door having'a second pole piece with an 5 rolled steel.

aperture therein, a, third pole piece having'a face portion shaped complementary to said magnetapertnre, said third pole piece haying a slidin fit in the aperture of said holder whereby [when said door .and said holder are moved towardsaid magnet said. third pole piece isdrawn bYhaagheticforce into. said magnet aperture to thereby seat on said first tpolewpiece said apertured second pole piece beingthereafter drawn-into engagement with said References Cited in the file of this patent UNITED. STATES PATENTS 2,288,688 Dubilier July 7, 1942 2,812,203 Scholten Nov. 5, 1957 FOREIGN PATENTS 696,676 .France Oct. .20, 1930 

